Spatial and Temporal Patterns of NDVI Variability in North East India (1998-2013)

Abstract

NDVI (Normalized Difference Vegetation Index) is designed to estimate the amount of above ground vegetation cover from measurements of red and near-infrared reflectance.It has been extensively used in vegetation related studies to estimate above ground biomass, crop yields, pastures etc. It is also related to other ground parameters such as leaf area index, photosynthetic level of plants, surface water and biomass extent. This paper used 10-day SPOT-Vegetation NDVI time-series data from 1998 to 2013 in Northeast India, to determine the spatial and temporal pattern of vegetation greenness in North East India and assess these changes during the period 1998-2013 used for 31 study sites based on the GLC 2009 landuse categories.The selected sites signify seven landuse categories. The main objective is to enumerate losses over different areas using remotely sensed data and also to figure out the health of vegetation and its growth with the help of Normalized Difference Vegetation Index (NDVI).The framework of this analysis is the use of coefficient of variation (CV) to determine the temporal changes in NDVI during the 16 year period and enables productivity changes under different climatic scenarios. A set of 3000 spatially distributed NDVI anomalies and Z-score were computed to remove the seasonal signal and to determine deviation of NDVI relative to the mean- monthly values of the 16 year period of the study area. From the analysis of NDVI value in different times, it is found that there was some fluctuation in the vegetation growth during the wettest months of each year.